Effects of rootstock and ground and fertigated applied nitrogen on productivity and fruit quality of `Fuji' apple was studied. In the fertigation portion of this project, treatments were as follows: 1) 22.4 kg N/ha per year, 2) 89.7 kg N/ha per year, 3) 89.7 kg N/ha per year plus 78.5 kg K/ha per year; 4) 156.9 kg N/ha per year; 5) 156.9 kg N/ha per year plus 78.5 kg K/ha per year. Fruit had optimum quality when leaf N concentrations were approximately between 1.9% to 2.15% dwt during light-cropping years and approximately between 2.12% to 2.40% during heavy-cropping years. Cross-sectional areas of `Nagafu-6 Fuji' trees were slightly smaller than those in `BC-2 Fuji' trees. Preliminary data also showed that mineral concentrations of leaves from various strains of `Fuji' do not significantly vary. In 1998, trees from 22.4 kg N/ha zone had lower leaf N, resulting in lower leaf area and lower photosynthesis but better fruit color than those with higher N applications. In 1998, trees on Ottawa-3 had higher yield than those on B.9, M.26, and M.7. Trees on B9 had lower leaf N and smaller fruit than those on other rootstocks. Fruit on M.7 rootstock were larger, but had the worst color among all rootstocks. Fruit on M.9 had better color than those other rootstocks. Trees with 2.43-m in-row spacing had significantly higher photosynthesis than those of 1.22-m spacing.
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